Fig. 6.

Endocrine cells do not arise from Sox9⁺ ducts during adulthood. (A) Schematic of the lineage tracing experiment in Sox9CreER^T2;R26R^YFP mice. Tamoxifen (TM) was administered daily for three days beginning at postnatal day P21 and pancreatic tissue was analyzed at P25 and P60. (B) The YFP lineage label is primarily detected in Sox9⁺ cells. (C) Quantification of YFP⁺ Sox9⁺ cells relative to the total number of Sox9⁺ cells (n=3). (D,E) Immunofluorescence staining reveals YFP⁺ SS⁺ PP⁺ cells and YFP⁺ Ins⁺ Glu⁺ cells closely associated with YFP⁺ ducts at P25 (insets in D) and P60 (insets in E). Asterisks indicate YFP⁺ hormone⁺ cells. (F,G) Quantification of YFP-labeled Ins⁺ Glu⁺ (F) or SS⁺ PP⁺ (G) cells relative to the total number of Ins⁺ Glu⁺ or SS⁺ PP⁺ cells, respectively (n=3). Values are grouped according to endocrine cell cluster sizes. Values are shown as mean ± s.e.m. Scale bars: 50 μm. Glu, glucagon; Ins, insulin; PP, pancreatic polypeptide; SS, somatostatin.